Pengaruh Penambahan Abu Sekam Padi dan Viscocrete 1003 pada Karakteristik Beton Geopolimer

Abstract

The use of cement as a binder in concrete has an environmental impact, because during the cement manufacturing process a large amount of CO2 emissions are released into the atmosphere. To overcome the problem of pollution, cement substitutes are needed. Geopolymer concrete is an alternative concrete that can be used to overcome the negative impacts of using cement concrete. Geopolymer concrete uses fly ash which contains high silicates and aluminates as a substitute for cement, because these two chemical elements can react with alkali activators and become binders. In addition, rice husk ash is a pozzolanic material that contains high silicate but low aluminate. The extent to which the characteristics of geopolymer concrete change with the mixing of these materials needs to be investigated. This study aims to determine the characteristics of polymer concrete, which include density, wave propagation velocity, compressive strength, and modulus of elasticity with the addition of rice husk ash and viscocrete 1003.The geopolymer concrete mixture in this laboratory experiment used a weight ratio of water to fly ash of 0.25, with a ratio of Na2SiO3: NaOH of 4:2. The concrete precursor material used was fly ash with a proportion of 444 kg per m3 of concrete. Viscocrete 1003 was added by 0.6% of the weight of the precursor, and rice husk ash was used as an additive material with variations of 0%, 5%, 10%, 15%, 20% of the weight of the precursor. The results of this study indicate that geopolymer concrete with the addition of 0% husk ash produces the highest values in the density test, compressive strength test, and wave propagation test, while the modulus of elasticity cannot be displayed because the compressive strength value is too small. The addition of rice husk ash to geopolymer concrete reduces the strength of the concrete. From these variations, the highest compressive strength value is 4.798 MPa. It can be concluded that the concrete in this study can be used for non structural elements in buildings.